In a photolithography process in a manufacturing process of a semiconductor device, for example, resist coating treatment in which a resist solution is applied onto a base film of a semiconductor wafer (hereinafter, referred to as a “wafer”) to form a resist film; exposure processing in which a predetermined pattern is exposed on the wafer; developing treatment in which the wafer after exposure is developed; etching treatment in which the base film or the like on the wafer is etched, and so on are performed, so that a predetermined circuit pattern is formed on the wafer.
In the aforementioned exposure processing, light is applied to a predetermined portion of the flat resist film to change the solubility of the exposed portion to a developing solution. In the developing treatment, when the developing solution is supplied to the wafer, the resist film at the exposed portion is selectively dissolved and removed, if it is, for example, a positive-type resist, resulting in a desired pattern of the resist film formed on the wafer. In the etching treatment, the base film being a lower layer is selectively etched with the resist film in the aforementioned predetermined pattern functioning as a mask (see, for example, Patent Document 1).
[Patent Document 1]
Japanese patent Application Laid-open No. 2002-75854
Incidentally, on the surface of the resist film which has been subjected to the aforementioned developing treatment, for example, a plurality of horizontal lines appear on the side wall surface as shown in FIG. 17, resulting in projections and depressions on the surface of the resist film R. This is conceivably caused by the wave property of light applied from above the wafer during exposure processing.